A record 25,000 researchers and exhibitors descended on San Francisco this week for the 2014 meeting of the American Geophysical Union (AGU). That number of attendees translates to a tremendous amount of Earth science being discussed via presentations and posters, and we can’t possibly cover it all in this blog. Fortunately, this buzz word graphic posted by @AGU_Eos helped us sort what attendees are talking about, at least on twitter at #AGU14.

Drought was certainly a hot topic, particularly California’s multi-year episode. NASA scientists announced at a press briefing that it would take about 11 trillion gallons of water (42 cubic kilometers)—or 1.5 times the maximum volume of the largest U.S. reservoir—to recover from the current drought. The calculation, based on data from the Gravity Recovery and Climate Experiment (GRACE) satellites, is the first of its kind. Read the full story here.

The buzz word “ice” probably stems from the abundance of research on Greenland that was presented on December 15. Scientists using ground-based and airborne radar instruments found that liquid water can now persist throughout the year on the perimeter of the ice sheet; it might help kick off melting in the spring and summer. Read more about those studies here. Look, too, at this new study that used satellite data to get a better picture of how the ice sheet is losing mass.

And finally, take a minute to browse some of the cool photos presented by Anders Bjørk of the Natural History Museum of Denmark, which included the portrait of Arctic explorers (below) and this image pair demonstrating glacial retreat in Greenland.

America’s Tiny Four Corners Region is an Outsized Methane Hotspot; TIME.com. One small spot in the U.S. Southwest is surprisingly the producer of the largest concentration of methane (CH4) gas seen across the nation. Levels of CH4 over the Four Corners region are more than triple the standard groundbased estimate of the greenhouse gas, as reported in a point study of satellite data by scientists at NASA/Jet Propulsion Laboratory (JPL) and the University of Michigan. CH4 is a heat-trapping gas whose increasing quantities in the atmosphere have fueled concerns about global climate change. The methane “hotspot,” seen on the map as a small splotch—see map above—measures approximately 6475 km2 (2500 mi2) at the junction of Arizona, New Mexico, Colorado, and Utah. For scale, the state of Arizona is about 292,668 km2 (113,000 mi2). But the area generated an annual 0.59 million metric tons of methane between 2003 and 2009—about as much CH4 as the entire coal, oil, and gas industries of the U.K. give off each year.

The Four Corners area (red) is the major U.S. hot spot for methane emissions in this map showing how much emissions varied from average background concentrations from 2003-2009 (dark colors are lower than average; lighter colors are higher). Image Credit: NASA/JPL-Caltech/University of Michigan

Scientists Say Ozone Layer is Recovering; Associated Press. Earth’s protective ozone layer is beginning to recover from its previously reduced levels, largely because of the phase-out since the 1980s of certain chemicals used in refrigerants and aerosol cans, a U.N. scientific panel reported. Scientists said the development demonstrates that when the world’s peoples come together, we can counteract a brewing ecological crisis. For the first time in 35 years, scientists were able to confirm a statistically significant and sustained increase in stratospheric ozone, which shields the planet from solar radiation that causes skin cancer, crop damage, and other problems. From 2000 to 2013, ozone levels climbed 4% in the key mid-northern latitudes at about 48 km (30 mi) above Earth’s surface, said scientist Paul Newman [NASA’s Goddard Space Flight Center (GSFC)].

Deep Ocean Hasn’t Warmed Measurably in a Decade, Says NASA; The Weather Channel. Deep below the ocean surface, there’s a place global warming hasn’t yet reached. According to a study published on October 5, 2014, in Nature Climate Change, scientists at NASA/Jet Propulsion Laboratory (JPL) have found that over the last decade the deepest part of the world’s ocean has not warmed measurably. The scientists analyzed ocean temperatures from between 2005 and 2013 and found that below a depth of approximately 2 km (~1.2 mi)—roughly halfway to the bottom at this location—the global ocean has not warmed nearly as quickly as the top half. The scientists collected the temperature data using both satellite measurements and data from the Argo array, a network of some 3500 floating probes scattered throughout the world that measure ocean temperatures and salinity. “The sea level is still rising,” said study coauthor Josh Willis [JPL] in a news release. “We’re just trying to understand the nitty-gritty details.”

Antarctic Sea Ice Level Breaks Record, NASA Says; CBSNews.com. Sea ice surrounding Antarctica is at an all-time high, even as global temperature averages continue to climb. NASA reports that ice formation in the continent’s southern oceans peaked this year, breaking ice-measuring satellite records dating back to the late 1970s. For the first time since 1979, on September 19, 2014, Antarctic sea ice extent exceeded ~20 million km2 (~7.7 million mi2) whereas the average maximum extent between 1981 and 2010 was ~19 million km2 (~7.3 million mi2). Despite this trend, sea ice as a whole is decreasing on a global scale. Researchers say that, just like global warming, trends have different outcomes in different parts of the world; not every location with sea ice will experience ice loss or gain. “When we think about global warming we would expect intuitively that ice should also be declining in the Antarctic region as in the Arctic,” explained senior research scientist Josefino Comiso [GSFC]. “But station and satellite data currently show that the trends in surface temperatures are most positive in the Arctic, while in the Antarctic region the trends are a mixture of positive and negative trends,” he said, adding that cooling and declining sea surface temperatures could also contribute to a “more rapid advance at the ice edge.”

1934’s Dust Bowl Drought Was the Worst in a Thousand Years for U.S.; NBCNews.com. The drought of 1934 wasn’t just bad, it was the worst. That’s the finding of a reconstruction of North American drought history over the past 1000 years, done by scientists from NASA and Columbia University’s Lamont-Doherty Earth Observatory. Their study, published in the October 17 issue of Geophysical Research Letters, concludes the drought of 1934, during the Dust Bowl years in the North American Plains, was 30% more severe than the next worst, which occurred in 1580, NASA scientists said. The scientists used tree ring records from 1000 to 2005 along with modern observations. They found that the 1934 drought extended across over 71% of western North America, compared with almost 60% during the 2012 drought. “It was the worst by a large margin,” said lead author of the study Ben Cook [NASA’s Goddard Institute for Space Studies—Climate Scientist]. The scientists found two main reasons: a winter high-pressure system over the West Coast that blocked precipitation and spring dust storms that suppressed rainfall.

GRACE Spacecraft Changed the Way Groundwater was Measured; CBS’ 60 Minutes. Leslie Stahl hosted a segment on California’s groundwater issues. The segment described the difficulty in sampling groundwater levels until NASA’s Gravity Recovery and Climate Experiment (GRACE) spacecraft was launched. Mike Watkins [JPL—GRACE Project Scientist] described how GRACE “can tell whether an area has gained water weight or lost it.” Jay Famiglietti [University of California, Irvine] said that he thought the method was “complete nonsense” until he started examining the data, which changed his position. The broadcast noted that Famiglietti was so worried by what he saw in the data that he is working “to alert governments and academics to the problem.”

Maybe you have heard people call Earth “the water planet.” The nickname is well-deserved. As this mosaic of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite conveys so well, the majority of Earth’s surface is covered by either liquid or frozen water. The atmosphere is awash with water as well. One satellite-based data set estimates that about 60 percent of Earth’s surface is covered by clouds (composed of water and ice droplets) at any given time.

Earth is home to yet another type of water—groundwater—which includes all the fresh water stored underground in soil and porous rock aquifers. Though groundwater is often forgotten because it’s not visible, more than two billion people rely on it as their primary water source.

With drought afflicting several parts of the world, and with aggressive use of groundwater in many agricultural regions, this precious water resource is under serious strain, warns NASA Jet Propulsion Laboratory hydrologist James Famiglietti. In a commentary published by Nature Climate Change in October 2014, Famiglietti wrote:

In many parts of the world, in particular in the dry, mid-latitudes, far more water is used than is available on an annual, renewable basis. Precipitation, snowmelt, and streamflow are no longer enough to supply the multiple, competing demands for society’s water needs. Because the gap between supply and demand is routinely bridged with non-renewable groundwater, even more so during drought, groundwater supplies in some major aquifers will be depleted in a matter of decades. The myth of limitless water and the free-for-all mentality that has pervaded groundwater use must now come to an end.

Image by J.T. Reager, NASA Jet Propulsion Laboratory.

Most of the major aquifers in the world’s arid and semi-arid zones—the parts of the world that rely most heavily on groundwater—are experiencing rapid rates of depletion because of water use by farms. As shown in the chart above—based on data collected by the Gravity Recovery and Climate Experiment (GRACE)—this includes include the North China Plain, Australia’s Canning Basin, the Northwest Sahara Aquifer System, the Guarani Aquifer in South America, the High Plains and Central Valley aquifers of the United States, and the aquifers beneath northwestern India and the Middle East.

The situation is looking particularly grim in California, a state currently suffering from extreme drought. The extent of the drought is visible in the series of GRACE maps of dry season (September-November) water storage anomalies shown below. Red areas show the height of the water in comparison to a 2005-2010 average. California’s Sacramento and San Joaquin river basins have lost roughly 15 cubic kilometers (4 cubic miles) of total water per year since 2011 — more water than all 38 million Californians use for domestic and municipal supplies annually. Over half of the water losses are due to groundwater pumping in the Central Valley, according to Famiglietti.

Image by Felix Landerer, NASA Jet Propulsion Laboratory.

The first step to managing the globe’s groundwater problem is to accept that we have one, Famiglietti recommends. And when societies are ready to look for solutions, the first place they’ll have to turn is the agricultural sector. “Agriculture accounts for nearly 80 percent of water use globally, and at least half of the irrigation water used is groundwater,” he wrote. “Even modest gains in agricultural efficiency will result in tremendous volumes of groundwater saved, or of water available for the environment or other human uses such as municipalities, energy production, industry and economic growth.”

See NASA’s Dazzling Proof that U.S. Air Quality Has Improved, Mashable.com. Summer in the U.S. is the time of year when humidity skyrockets, air stagnates, and the air quality deteriorates, especially downwind of the coal-fired power plants and manufacturing plants of the Ohio Valley. During hazy and hot summer days in the big cities along the Interstate 95 corridor, the sky often looks like the visual equivalent of white noise—with the horizon indistinguishable from the milky sky. Yet air quality has actually been steadily improving over the past few years, largely thanks to the Clean Air Act, along with a drop in coal use and dramatic changes in vehicle fuel efficiency and emissions. NASA has released beautiful images demonstrating that people in major U.S. cities from Los Angeles to New York are breathing less nitrogen oxide. The data come from the Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite. Nitrogen dioxide is one of the six common pollutants the EPA regulates to protect human health. It can harm the respiratory system and also combines with other pollutants to form smog. Nitrogen dioxide is mostly produced by burning gasoline in vehicle engines and from burning coal. “While our air quality has certainly improved over the last few decades, there is still work to do—ozone and particulate matter are still problems,” said atmospheric scientist Bryan Duncan.

Water Weight Used to Calculate the Amount of Snow in California with GPS, Scientific American. Water weighs about 8.3 pounds per gallon (1 kg/L). Now, scientists have developed a way to use water’s weight to measure just how much snow is covering mountains in the western U.S. In states like California, currently in the midst of a crippling drought, the more water managers know about how much snow is in the mountains, the better they can plan for the summer months ahead. More accurate information about such snowpack can help these managers and hydrologists plan for how to fill reservoirs, how much water they might have available during the dry season, and how dry the soils might be during fire season. They’ll also get a better fix on future levels of reservoirs for hydroelectric power generation. Donald Argus, a research scientist and geophysicist at JPL, recently published a study outlining the new technique in the journal Geophysical Research Letters. If scientists know the height of a piece of land in summertime, and the height when snow covers it, they can use the difference to calculate how much snow is sitting on the mountains. The technique uses a dense network of global positioning system (GPS) sites scattered across the Western U.S.

Scientists Warn of Rising Oceans From Polar Melt, The New York Times. A large section of the mighty West Antarctica ice sheet has begun falling apart and its continued melting now appears to be unstoppable, two groups of scientists reported on May 12, 2014. If the findings hold up, they suggest that the melting could destabilize neighboring parts of the ice sheet and a rise in sea level of 10 feet (about 3 meters) or more may be unavoidable in coming centuries. Global warming caused by the human-driven release of greenhouse gases has helped to destabilize the ice sheet, though other factors may also be involved, the scientists said. The rise of the sea is likely to continue to be relatively slow for the rest of the twenty-first century, the scientists added, but in the more distant future it may accelerate markedly. The West Antarctic ice sheet sits in a bowl-shaped depression, with the base of the ice below sea level. Warm ocean water is causing the ice sitting along the rim of the bowl to thin and retreat. As the front edge of the ice pulls away from the rim and enters deeper water, it can retreat much faster than before. In a new paper published in Geophysical Research Letters, a team led by glaciologist Eric Rignot used satellite and airborne measurements to document an accelerating retreat of six glaciers draining into the Amundsen Sea region. With updated mapping of the terrain beneath the ice sheet, the team was able to rule out the presence of any mountains or hills significant enough to slow the retreat.

NASA Places Radar in North Carolina to Study Rain in Smokies, Washington Times. NASA placed two radars on land in Rutherford County, North Carolina, for a field campaign to study rainfall in the Great Smoky Mountains. The campaign ran from May 1 to June 15, 2014. “We have set up rain gauges and radars across the area to learn more about how weather and rain systems behave in the mountains,” said research scientist David Wolff. The campaign was designed to validate data from the Global Precipitation Measurement (GPM) mission’s Core Observatory, which launched in February 2014. The science team expected to end the six-week campaign with detailed data to improve their understanding of both the fundamental sciences of mountain rainfall and how best to estimate rainfall using satellite observations over remote and rugged regions. Scientists will use what they learn to improve weather predictions and flood warnings. Team members will take a break after the summer and are scheduled to travel to Seattle, Washington, in 2015-16 to measure winter weather there.

NASA ‘Balloon Campaign’ Goes to Australia, International Business Times. NASA and the University of Wyoming teamed up with the Australian Bureau of Meteorology (BOM) in Darwin, Australia, for a balloon-based campaign designed to better understand the composition and behavior of volcanic plumes. The Kelud Ash (KlAsh) experiment involved launching a series of balloons to take measurements of emissions from the volcano in Indonesia. Mt. Kelud sent small droplets of sulfuric acid—as ash particles and sulfate aerosol—up to 15 mi (25 km) above Earth when it erupted in February this year. Principal investigator Duncan Fairlie said: “The purpose is to better characterize particle sizes, composition, and optical properties from a relatively fresh volcanic plume in the stratosphere.” The two-week balloon campaign, which started on May 14, 2014, launched small balloon payloads over the Indian Ocean from the bushes of Darwin territory. Fairlie said the team sampled the volcanic plumes at an altitude of around 12 miles (20 kilometers) in all flights.

The magnitude of fluorescence portrayed in this visualization prompted researchers to take a closer look at the productivity of the U.S. Corn Belt. The glow represents fluorescence measured from land plants in early July, over a period from 2007 to 2011.

Under the Summer Sun, the Corn Belt Is the Most Biologically Productive Place on Earth, Smithsonian Magazine. Rainforests, whether in the Amazon, Southeast Asia, or Central America, are hotspots of organic productivity. Fueled by abundant rain and a reliable stream of nutrients, the Amazon blooms year-round. For a brief period each summer, however, the ingenuity of humankind trumps even the mighty rainforests at biological production. A group of researchers, including Christian Frankenberg and Joanna Joiner have determined that during peak growing season, the Midwest U.S. Corn Belt is the most productive land on Earth. In other words, there’s more photosynthesis going on here than in the Amazon. When plant cells photosynthesize, part of the energy they produce is emitted as fluorescent light. By measuring the strength of this fluorescence from space, scientists can get a measure of plant productivity.

Arctic Melting Is Lasting Longer and Affecting More Ice,UniverseToday.com. The Arctic melt season is averaging five days longer with each passing decade, a new study by NASA and the National Snow and Ice Data Center reveals. More ice-free days mean the water (which is darker than the surrounding ice) is exposed longer and can absorb more of the Sun’s heat, further increasing the melting rate and extent. The study shows that thickness of the Arctic ice cap has shrunk by as much as 1.2 meters (4 feet). By the end of this century, scientists believe the Arctic Ocean will be ice-free during the entire summer. This news came in the same week that the Intergovernmental Panel on Climate Change released its own report on global warming. Data were collected with NASA’s (long-deceased) Nimbus-7 Scanning Multichannel Microwave Radiometer and instruments onboard Defense Meteorological Satellite Program spacecraft. Scientists can measure the changes in the ice’s microwave emissivity using a formula developed by co-author Thorsten Markus.

NASA Study Projects Higher Temperatures Despite Recent Slowdown in Global Warming,Bloomberg. Despite a recent slowdown in the rate of global warming, a study by Drew Shindell suggests global temperatures will likely continue to rise in coming decades, on track with earlier estimates of increasing temperatures. Shindell and his colleagues sought to reconcile different estimates for the Earth’s climate sensitivity, or how temperatures change in response to changes in radiative forcing. Some studies estimate low climate sensitivity, based on the assumption that global average temperatures would respond uniformly to increases of carbon dioxide (CO2) and other greenhouse gas emissions. But the NASA study showed that global temperatures are more sensitive to changes in aerosols and ozone in the atmosphere than was thought. This higher sensitivity could mean a larger and faster temperature response. Shindell said the study’s findings could have “a really profound impact” on the amount of greenhouse gas emission reductions needed for countries to meet an international goal of limiting temperature increases to 2°C (3.6 °F). “I wish it weren’t so,” said Shindell, “but forewarned is fore-armed.” Global temperatures have increased at a rate of 0.12 °C (0.22 °F) per decade since 1951, according to the NASA GISS temperature record. This trend has been interrupted since 1998, as since then the rate of warming has slowed to only 0.05 °C (0.09 °F) per decade—even as atmospheric CO2 continues to rise.

Amazon Rainforest Breathes In More Than It Breathes Out,LiveScience.com. A new study further confirms that pristine Amazon forests pull in more CO2 than they put back into the atmosphere, helping to reduce global warming by lowering the planet’s greenhouse gas levels. When scientists account for the world’s CO2, their totals suggest some of the greenhouse gas disappears into land-based carbon traps. These natural carbon sinks, such as forests, absorb and store CO2, helping to lower the greenhouse gas levels in the atmosphere. To better measure the carbon flux from the Amazon, researchers tracked tree death throughout the Amazon. Lead study author Fernando Espírito-Santo combined satellite data, airborne lidar data (i.e., laser surface imagery), and tree counts to compare carbon consumed by living trees with emissions from dead trees. Espírito-Santo found that dead Amazonian trees emit an estimated 1.9 billion tons (1.7 billion metric tons) of carbon to the atmosphere each year. In a normal year, the Amazon rainforest absorbs about 2.2 billion tons (2 billion metric tons) of CO2, studies suggest. The study also found that big storms that can blow down millions of trees at once barely budge the forest’s carbon output.

It’s that Time of Year
Monarch butterflies congregate in central Mexico every winter. Sandhill cranes stop at a small section of the Platte River in Nebraska every spring. And earth and planetary scientists congregate in San Francisco each December.

Tracking Tornado IntensityAre tornadoes getting stronger? It’s a complicated and controversial topic among meteorologists, but Florida State University’s James Elsner thinks the answer is probably yes (with an emphasis on probably). Elsner came to that conclusion after analyzing the damage caused by every tornado to hit between 1994 and 2006. “If I were a betting man, I’d say tornadoes are getting stronger,” he noted during a talk the American Geophysical Union meeting this week. But when asked directly at a press conference whether they were, he resorted to caveats, according to Scientific American. “I’m not doing this [work] to establish the future intensity of tornadoes,” he explained, but to establish a method that someday could indeed determine if the storms are becoming more powerful. For more on the muddled topic of tornado intensity trends, see this detailed post from DotEarth’s Andrew Revkin.

Arctic Cyclones Galore
Remember that strong Arctic storm that whirled near the north pole back in the summer of 2012? A new analysis shows that there are more of them than we thought—40 percent more. From 2000 to 2010, about 1,900 cyclones churned across the top of the world each year, leaving warm water and air in their wakes—and melting sea ice in the Arctic Ocean. “We now know there were more cyclones than previously thought, simply because we’ve gotten better at detecting them,” one of the authors explained. “We can’t yet tell if the number of cyclones is increasing or decreasing, because that would take a multidecade view.” Read the press release.

Data Visualization AMAIf you missed the Reddit Ask Me Anything with Earth Observatory art director Robert Simmon, you can find the transcript here.

From FacebookWe post items every day to facebook (and not everything that goes onto Facebook makes it onto our site). One of the highlights this week was a spectacular montage of astronaut photography put together by film student David Peterson. Look for Don Pettit’s head peering out from the cupola at the end end of the video. If you’re anything like me, you’ll find yourself watching it again. And again. And again.

Agony in the Philippines
Satellite images of Super Typhoon approaching and smashing into the Philippines last week were extremely worrisome. Reports and imagery from the ground have now confirmed that the concern was justified. One of the most intense tropical cyclones ever measured by satellites has left the Philippines in chaos. The Capital Weather Gang has heartbreaking footage from Earth UncutTV, which had videographers working in the path of the storm.

Deadly Cyclone over SomaliaScores of people have died in Somalia after another powerful tropical cyclone— known as 03A — slammed into the northeastern part of the country. According to Accuweather, about 1-2 tropical cyclones form in the Arabian Sea each year, often in November. The last cyclone to strike Somalia made landfall in December 2012. Read more about the storm from Voice of America and Gulf Today.

Super Typhoon Haiyan and Climate Change
Given the strength and destruction of Haiyan, it was inevitable for discussions to arise about the relationship between the most powerful tropical cyclones and climate change. Climate Central contacted some of the leading researchers in the field and detailed some of the complexities in this piece. Though not all experts agree, the general consensus is that warming will bring stronger, wetter, but less frequent storms in the coming decades. Read our feature about storms and climate change for more insight on this complicated balance.

New Clues about Chelyabinsk MeteorFollowing the dramatic meteor explosion over Chelyabinsk on February 15, 2013, eye-popping video and photographs flooded social media. After the event, there was no shortage of speculation about the trajectory of the meteor and how the explosion created so much damage. Scientists have since had time to carefully review all of the available evidence and have just published a detailed analysis of the event in the journal Science. Read more about the new research from NASA Ames and check out this blog about one of the researchers who co-authored the study.

Tiger Stripes Beneath Antarctic Ice
A new study published in Science points out that stripes of dirt and rock beneath Antarctic glaciers create friction zones that slow the flow of ice toward the sea. The researchers focused on the Pine Island and Thwaites glaciers, which together have contributed about 10 percent of the world’s observed sea-level rise over the past 20 years. Read more about the research in this press release from Princeton.

From Facebook: Eclipse at 44,000 Feet
Flying at 44,000 feet (13,000 meters), eclipse chasers on a chartered jet managed to intercept the Moon’s shadow over the Atlantic Ocean during the November 3, 2013, solar eclipse. The remarkable flight made a perpendicular crossing of the central shadow track. The photograph below was taken by Ben Cooper of Launch Photography. See another unique view—from space—of the same eclipse here.

The following is an excerpt from a story by Alan Buis, NASA’s Jet Propulsion Laboratory…

The curtain has come down on a superstar of satellite oceanography that played the “Great Blue Way” of the world’s ocean for 11.5 years. The joint NASA and Centre National d’Etudes Spatiales (CNES) Jason-1 ocean altimetry satellite was decommissioned on July 3, 2013, following the loss of its last remaining transmitter.

Launched December 7, 2001, and designed to last three to five years, Jason-1 helped create a revolutionary 20-plus-year climate data record of global ocean surface topography that began in 1992 with the launch of the NASA/CNES Topex/Poseidon satellite. For more than 53,500 orbits of our planet, Jason-1 precisely mapped sea level, wind speed, and wave height for more than 95 percent of Earth’s ice-free ocean every 10 days. The mission provided new insights into ocean circulation, tracked our rising seas, and enabled more accurate weather, ocean, and climate forecasts.

“Jason-1 has been a resounding scientific, technical and international success,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate in Washington. “Since launch, it has charted nearly 1.6 inches (4 centimeters) of rise in global sea levels, a critical measure of climate change and a direct result of global warming. The Jason satellite series provides the most accurate measure of this impact, which is felt all over the globe.”

During parts of its mission, Jason-1 flew in carefully coordinated orbits with both its predecessor Topex/Poseidon and its successor, the Ocean Surface Topography Mission/Jason-2 (launched in 2008). These coordinated orbit periods, which lasted about three years each, cross-calibrated the satellites, making possible a 20-plus-year unbroken climate record of sea level change. These coordination periods also doubled data coverage.

Combined with data from the European Space Agency’s Envisat mission, these data allow scientists to study smaller-scale ocean circulation phenomena, such as coastal tides, ocean eddies, currents, and fronts. These small-scale features are thought to be responsible for transporting and mixing heat and other properties–such as nutrients and dissolved carbon dioxide–within the ocean.

Contact was lost with the Jason-1 satellite on June 21 when it was out of visibility of ground stations. At the time of the last contact, Jason-1 and its instruments were healthy, with no indications of any alarms or anomalies. Subsequent attempts to re-establish spacecraft communications from U.S. and French ground stations were unsuccessful. Extensive engineering operations undertaken to recover downlink communications also were unsuccessful.

After consultation with the spacecraft and transmitter manufacturers, it was determined a non-recoverable failure with the last remaining transmitter on Jason-1 was the cause of the loss of contact. The spacecraft’s other transmitter experienced a permanent failure in September 2005. There now is no remaining capability to retrieve data from the Jason-1 spacecraft.

On July 1, mission controllers commanded Jason-1 into a safe hold state that reinitialized the satellite. After making several more unsuccessful attempts to locate a signal, mission managers at CNES and NASA decided to proceed with decommissioning Jason-1. The satellite was then commanded to turn off its magnetometer and reaction wheels. Without these attitude control systems, Jason-1 and its solar panels will slowly drift away from pointing at the sun and its batteries will discharge, leaving it totally inert within the next 90 days. The spacecraft will not reenter Earth’s atmosphere for at least 1,000 years.

“Like its predecessor Topex/Poseidon, Jason-1 provided one of the most comprehensive pictures of changes in the tropical Pacific Ocean, including the comings and goings of El Nino and La Nina events,” said Lee-Lueng Fu, Jason-1 project scientist at NASA’s Jet Propulsion Laboratory. “These Pacific Ocean climate cycles are responsible for major shifts in sea level, ocean temperatures and rainfall every two to five years and can sometimes be so large that worldwide weather patterns are affected. Jason-1 data have been instrumental in monitoring and predicting these ever-changing cycles.”

An image from the SEVIRI instrument aboard the European Space Agency’s Meteosat-10 geostationary satellite. The vapor trail left by the meteor is visible in the center of the image. Credit: European Space Agency/EUMETSAT

Around 9:20 a.m. local time on February 15, 2013, a blazing mass of rock from space—a meteor—streaked across the sky over the Ural Mountains in the Chelyabinsk region of Russia. The burning mass produced a loud sonic boom and shock wave that blew out windows in multiple cities and towns. Russian media outlets are reporting hundreds of injuries, most minor, and damage to thousands of buildings.

Bill Cooke, the head of the Meteoroid Environments Office at Marshall Flight Center, said that the object, which likely came from the asteroid belt, had a diameter of about 15 meters (50 feet) and weighed about 7,000 metric tons. When it encountered the top of Earth’s atmosphere, it was moving 18 kilometers (11 miles) per second and left a vapor trail that was approximately 480 kilometers (300 miles) long. It lasted in the atmosphere for over 30 seconds before breaking up 25 kilometers (15 miles) above the surface, producing a violent explosion that released about 300 kilotons of energy. Most of the fragments burned up as they passed through the atmosphere, but some meteorites did reach the surface. One reportedly left an impact crater that was 6 meters (20 feet) in diameter.

The incident was not related to 2012 DA14, a 45 meter (150 foot) diameter asteroid that was expected to make its closest approach to Earth—17,200 miles (27,000 kilometers)—at 2:25 p.m. EST on Feb 15, 2013. The trajectory of the Russian meteor was significantly different than the trajectory of the asteroid 2012 DA14.